The present invention relates to a method and apparatus for standardizing ultrasonography training, and more particularly, a method and apparatus for standardizing ultrasonography training using image to physical space registration of tomographic volumes from tracked ultrasound.
There are a number of medical imaging and instrumentation systems presently available including Positron Emission Tomography (PET), Magnetic Resonance Imaging (MRI), computed tomography (CT) and ultrasound. CT and MRI are imaging modalities that provide tomographic slices of the imaged volume.
CT and/or MRI used in combination with other imaging modalities, provide more useful information for the staging and treatment of cancer. For example, using CT and ultrasound can provide better diagnostics as well as the potential for spatial orientation of the patient and/or the area of interest.
A fundamental force in the development of surgery and other forms of directed therapy is the need to increase the information available to physicians and to place that information in both spatial and temporal contexts. The field of interactive image guided procedures (IGP), as it is known today, began in the 1980's and focused on tracking the surgical position in the physical space and display position in image space. This technique was first used in the field of neurosurgery and eventually crossed over into many other medical fields. IGPs have four basic components including image acquisition, image-to-physical-space registration, three-dimensional tracking, and display of imaging data and location. There has been much concurrent advancement in these four areas, which is a necessity for the timely incorporation of IGP into common medical practice.
A system of interest utilizes a scan technology such as CT in combination with an ultrasound instrument, such as an endorectal ultrasound (ERUS) probe, that is tracked for position in physical space in order to display position in image space. Such a system provides much more diagnostic information, but training students and technicians on even general ultrasonography is a somewhat complicated undertaking. Ultrasound image interpretation is associated with a significant learning curve.
Currently practical, as opposed to didactic, ultrasonography training is performed by trainees practicing on live patients and then learning disease processes from mentors. The training is serendipitous at best since a trainee practices only on the available test patients and not a wide variety of test patients suffering from a wide variety of diseases or disorders. The current approach to training in ultrasonography generally utilizes classroom training and education in the theory and physics of ultrasound measurements. Once this is completed the trainee goes through extended on the job training by practicing and learning on real patients under the guidance of an experienced radiologist. In some specialties this may require working with 50 to 100 patients. In a clinical setting, the flow of patients is irregular and unpredictable. Therefore, the duration of training is unpredictable. By using the time of a radiologist or other skilled imaging specialist along with the trainee, the time and cost expended is significant by the time the trainee is sufficiently “certified” to independently acquire and/or interpret images.
Thus, presently available ultrasonography training is provided with models that may not be realistic and certainly are limited by the number and expense of multiple models with which to train. There are more than 25,000 registered ultrasound technicians. There are different specialties within ultrasonography. The testing is standardized and involves static exams after a training and schooling period. Thus, it is desirable to provide an ultrasonography training system that permits the trainee to view more images of particular areas of interest for specialization and for improving training.
One ultrasound training system is disclosed in U.S. Pat. No. 5,609,485 (Bergman et al.). Bergman et al. disclose a medical “reproduction system” for use in training. The medical reproduction system is a computer-based, interactive system for use by physicians and technicians in medical training and diagnosis by means of medical instrumentation such as ultrasound machines. The system of Bergman et al. collects ultrasound data and creates a training system using simulated tools (e.g., ultrasound machine, transducer and mannequin). Bergman et al. suggest that the system can be used for offline diagnosis by a technician or physician at some time after an actual patient scan or ultrasound. However, Bergman et al. does not provide an assessment of the accuracy of the acquired ultrasound volumes, and therefore, there is no detail as to how the system would be useful as a clinical diagnostic tool.
It is desirable to provide a method and apparatus for standardizing ultrasonography training using image to physical space registration of tomographic volumes from tracked ultrasound. It is desirable to provide a technology that would shorten, standardize, and broaden the training for technicians as well as radiologists and surgeons. It is desirable to use “spatially-oriented” ultrasound images for training of physicians, technicians and nurses in the use and interpretation of ultrasound images for various portions of the anatomy.